Interest-computing device.



M. STEVENS.

INTEREST COMPUTING DEJICE.

APPUCATION FILED JULY 3.19%. 1,209,349. Emma 1m. 19, mm.

Inventor Attorneys Witnesses IKEREILL STEVENS, OF .IOPEKA, KANSAS.

INTEREST-C(IMPUTZNG DEVKCE.

1 35 43 349; Specification of Letters Patent.

Patented Dec. 19. .1916.

Application filed July 3, 191E. Serial No. 107,390.

To a. whom it may concern.-

Be it known that 1, MERRILL SIEVENS, a citizen of the United States, residing at "iogeka, in the county of Shawnee and State 5 o? Kansas, have invented a new and useful interest-Computing Device, of Which the folio ring is specification.

The present invention is it device for cnlsting or computing interest, and it is the object of the invention to proride u very mole and inexpensive yet thoroughly practicel, convenient and eilicient device of that character for readily ascertaining with absolute accuracy the interest on various amounts at any rate of interest for any iuunb-er oi? days or between tvvo given (lilies, sir-1 weli {is quickly determining the number oi? days between any two dates or determining the due date from a certain date given numb. of days for which other ioci is to run.

going and other objects in the foii. view which will appear ns the description proceeds, the invention resides in the combiniitionenu arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed can be made he scope of vvhat is claimed Without from the spirit of the invention. vention is i ustrated in the accomdrewing, wherein l ise, plan view or" the device. an nlarged iragmentnl plan view ustrate the index tab and adis a section on the Fig. is n bottom view own in Fi Fig. i he 55 of Fi 1 illuso L the invention, there are erposed disks 1 and 2 coinany other suitable 2. being of siightlv the lower disk .1,

ver disk than be ng ii. bushing 3 huvupon the ends thereprovided with con through the bushing; 3 and serves as a pivot for connecting the two disks whereby they can be rotated relative to one another.

The upper disk 9. has printed or olheiuvise provided thereon a concentric circular line (3, and. radial lines 7 extending from the line 5 to the margin of the disk and dividing the marginal portion of said disk into twelve month divisions, one for each u'ionth of the your. The disk 2 is further provided with 2 second circular line 9 between the line 6 and the margin of the disk and the annular column between the line i) and margin of the disk is provided with radial lines 10, sub-dividing each month division 8 into the proper number of day sub-divisions, and said sub-divisions of each month division are numbered consecutively from i HPWltid to 28, 30 or 81 according to the number of days in the particular month.

The day subdivisions are all of uniform size, while the month divisions are of a length proportional to the number of (hays thereof.

The lower disk 1 is provided upon its upper surface with a circular line 11 between the margin of the two disks, and the upper surface of the disk 1 is provided with radial lines 12 between the margins of the two disks. The line 11 provides two annular columns divided by the lines 12 into .the soiices and 14, respectively. The spaces 13 are numbered from 1 to consecutively, this being an intermediate "column between the inner column upon the upper surface of the upper '(llSk Q, and the outer column upon tle disk 1 adjacent the margin there/oi. Said outer column of the disk 1 has its spaces 1% bearing the interest in dollars on 331000 at one per cent. for a number of days corresponding to the number of days of the your indicated by the numeruh in the intermediate column of spaces 13. The outer column can have the interest in diczited thereon in other units upon various sums and at various roles of interest, but the foregoing is exceedingly practical in use.

The lower disk 1 is provided with a. slit 15 whose terminals extend radially along certain lines 12, and whose intermediate portion extends inwardly beyond margin of the upper dislr. This slit 15 provides an i wardly projecting index tab 15 which is sprung upwardly so as to overlap and rest upon the upper surface of the marginal portion oi the upper disk 2. @nc edge of the tab 15 is on the division line between the numerals l and 365 of the intermediate column, and the tab is orovided at that edge and adjacent its free inner end with an angular notch 16 providing an offset edge 1?. 'lhe tab is is prefeiobly provided tiereon along; the edge 17 with on area 18 colored red or any other suitable color to attract attention to said edge, and to facilitate the setting of the disk 2 The marginal portion of the disk 2 fits snugly iiinderneath the tab 15, and is held snugly upon the disk 1 by the tension oi? said tab. Said tab tends swing into the plane of the disk 1, and in this manner, the two disks are to which they are rotated relative to one another. s

in the table composed of the three nines, no account is taken of Febru 5 29,, and for terms ofdsys in leap year such date is. essed one (la sl'iould ii, added can be readily done by movingthe which dislzQ ahead to bring the next day numb Within the notch 16., For terms of days leap years. the annular table upon the owe or each surfaee of the disk 1 should be con, sultel'l.v Thus thebsol; or lower surlace the annular llne the disi: l is provided with lli radial lines 1%", and annular cole 1's 1?} and 1 1- correspondng to the parts desig nated ll, l2, l3 and 1 upon the upper stir Face of the disk 1, with the e: -;ception that in the table upon the'bnck of the disk or card l, the columns 13 and H are divided into 366 spaces for lealp year, end the interest tor spaces 1 figured.aceonlingly; 1

The use the present" device is best enby examples.

to bring the desiration Dec. l n 1h ll; of tab 15 next to the offset ed e the designation Aug: twillbe found registering; with the min the middle column. 273 is the interest days from 1 cent the numeral. 273 in the middleleol appears in the outer circle 7.4t'l9 l52-ii1terest held in position nple 1: ll'a'nted-interest at 5% on Iiom lJee. l to Aug. 31: Rotate the on" snow were days on see-da gets. at 1%:

e800 .e slow 5 .e eye 4 i X 7.479e-52 seem, all s which readily computed mentally from the Example 2: Wanted-due date on for sixty days dated May 1: Bring designation 1 Within jncent the offset edge 17, and the designs.

the notch 16 tion 60 in the middle column- Will indicate miter of in .ln the event of leap year, 'When the inter-e I est period runs pest February 29, one number 15 added to the indicated number of the nnddle column, and then the tsble on the back of the disk or card 1 1s consulted for the interest unit.

I illaving thus described the invention,

is claimed as new is:

It fconlputing device embodyin T 21 card ands disk-mounted for rotation thereon, dha'vi'ng slit Whose terminals proalia'lly outward; said slit providing n erdlyprojecting spring index; tab flopping the margin of e] disk upon the card, the card 111g radial-lines providing an annular colurnn'of speces adjacent to theed'ge of the disk, said spaces being graduated starting from one edge of the tab, the disk having redial lines providing an annular column of spaces at the edge of the disk cooperable with the aforesaid spaces, said tab having a, notch at said edge and adjacent to its free end providing at offset edge with which the lines of the disk lire registrable, said notch being of a size to receive one of the spaces of the annular' COllUll-ill of the disk.

In testimony that l claim the foregoing as my oivnylfhave hereto affixed my signe- 'ture in the presence of two Witnesses.

MERRILL srsvisns.

the disk to press 

